The present invention relates generally to push/pull type door latch assemblies having paddle style handles of the type used in hospitals, nursing homes, clinics, schools, and other facilities. More specifically, the present latch assembly is designed for applications where it is desired to reduce the chances of cords, wires and/or ropes or the like (hereinafter referred to as “ligatures”) being caught on the latch assembly or handle.
Door latches keep a door from opening until an operator disengages the door latch bolt by maneuvering one of the handles. Rotating knob, lever, and push/pull paddle type door handles are known in the art. Because no rotational movement is required to operate push/pull door handles, they are commonly used in health care and educational facilities such as hospitals, nursing homes and schools. One desirable feature of push/pull door handle and latch assemblies is that easy, hands-free opening of a door is possible. Push/pull door handle assemblies conventionally operate so that the door opens with a pushing action on a handle on one side of the door, and with a pulling action on a handle on the other side of the door.
Examples of existing push/pull door latch assemblies are described in U.S. Pat. Nos. 6,293,598; 7,258,374; 7,481,607; 6,196,599 and U.S. Pat. No. 5,730,478, all commonly assigned to Architectural Builders Hardware Manufacturing, Inc., and hereby incorporated by reference. Such door latch assemblies include, generally, a latching mechanism, at least one handle assembly and at least one cam assembly.
In conventional applications, a pull handle of a door latch assembly is mounted on the side of the door toward which the door opens into a room interior, and a push handle of the door latch assembly is mounted on the opposite side of the door. Other configurations are contemplated depending on the application. These assemblies typically incorporate a cam which transfers motion from the pushing or pulling movement of the handle to rotate a drive shaft extending through an opening in a latch cylinder. When rotated, the drive shaft withdraws the door latch, against the force of a return spring, to release the door. Generally, only a small amount of force in one direction is sufficient to release the latch.
In some health care facilities, there is a need for a push-pull latch assembly similar to those described above that is resistant to ligatures becoming caught on portions of the assembly.